Scientists at NASA discovered a freshly made crater on Mars, but it was two years before they noticed the remarkable cavity on the planet's surface. Still, it is the first-ever impact that was recorded with before-and-after images.
The Mars Reconnaissance Orbiter, which has been in the Red Planet's orbit since 2006, spotted the new crater through its weather-monitoring camera dubbed as the Mars Color Imager, or MARCI. MARCI is tasked to look for dust storms and other phenomenon that is most likely caused by the planet's own weather systems, and then send the images back to the space agency.
"It wasn't what I was looking for," said Bruce Cantor, the scientist in charge of MARCI's daily coverage of Mars. "I was doing my usual weather monitoring and something caught my eye. It looked usual, with rays emanating from a central spot."
Cantor's job is crucial since he has to deliver reports about the weather on Mars, especially to the team commanding Opportunity, a long-time solar-powered resident of Mars, about whether natural disturbances on Mars could affect its operations. Every day he has to check and review the images captured by MARCI. Two months ago, one particular shot caught his eyes.
One image of the equator showed a large dark spot. Curious, Cantor checked previous images a month or more at a time. He learned that the spot was already there last year but it did not show up in the images in the last five years. Finally, he narrowed down the search and, in an eureka moment, discovered that the crater was not there until March 28, 2012.
For a clearer image of the crater, NASA used Reconnaissance's ultra-sharp camera called the High Resolution Imaging Science Experiment (HiRISE) two months after Cantor's discovery.
The crater, slightly elongated in form, is about half the size of a football field on Earth. Measuring up to 159 by 143 feet, the depression is likely caused by an inevitable contact between an asteroid and the atmosphere of Mars, which is situated just next to the infamous Asteroid Belt, scientists said.
"The biggest crater is unusual, quite shallow compared to other fresh craters we have observed," said Alfred McEwen, a principal investigator of HiRISE from the University of Arizona in Tucson.
Scientists said the impact was also similar to the meteor impact in Chelyabinsk, Russia, over a year ago, a shocking incident that created panic among the locals, shattered windows of every establishment in the city and caused injury to 1,500 people in the area.
